Recently siding boards embossed to give a preferable design are diffused in the housing market. Especially siding boards having appearance in which square blocks having natural stone like surface are combined intermediating joint grooves have advantageously been used.
The material of said siding board is mainly inorganic board such as wood-cement board and the like and to manufacture embossed siding board using inorganic board as material, dry or semi-dry method or wet method is applied. In said dry or semi-dry method, a mixture consisting substantially of an inorganic curable material such as a cement and the like, and reinforcing wood material such as wood flake, wood wool, wood fiber, wood pulp and the like is strewed on the mold plate to form a dry mat and said dry mat is pressed with said mold plate to transfer the pattern of said mold plate to the surface of said dry mat and then said embossed dry mat is cured. On the other hand, in said wet method, said mixture consisting substantially of an inorganic curable material and a reinforcing wood material is dispersed in the water to prepare slurry and a dehydrated wet mat is formed on a net or felt by using said slurry by paper making method and then said dehydrated wet mat is pressed by a mold plate to transfer the patterns of said mold plate to the surface of said dehydrated wet mat and then said embossed wet mat is cured.
Said dry or semi-dry method has a disadvantage in that a large number of the mold plates should be prepared in the embossing process, which makes production inefficiency since the formed dry mats are pressed respectively with mold plates, while said dry or semi-dry method has an advantage in that deep embossing is easy for said dry mat since said dry mat has a coarse structure. On the other hand, said wet method has a disadvantage in that deep embossing is difficult for said wet mat since said wet mat has a close structure while said wet method has an advantage in that only one mold plate may be prepared for each line, which makes production efficient since the formed wet mat is successively pressed by a mold plate in the embossing process.
Wet-dry method in which a dry mat is formed on a wet mat by strewing the mixture of an inorganic curable material and a reinforcing wood material on a wet mat formed by paper making method to pick up advantages of both dry and semi-dry method and wet method (Japanese Patent Application No. Hei-6-292052).